• Journal of Life Science
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• v.22 no.1
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• pp.1-6
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• 2012

The present study examined the effects of consumption of Jeju ground water containing vanadium components on oxidative stress in obese (ob/ob) mice. Intake of Jeju ground water decreased the generation of oxidative stress induced-lipid peroxidation in the liver of ob/ob mice It also enhanced the enzymatic antioxidant defense system by increasing the protein expression and activity of superoxide dismutase, catalase, and glutathione peroxidase in liver tissues. Jeju ground water intake also upregulated the intracellular content of reduced glutathione. The induction of antioxidant enzyme expression by consumption of Jeju ground water was mediated by the erythroid transcription factor NF-E2 (Nrf2). Increased nuclear expression of phospho Nrf2 was observed in ob/ob mouse liver cells following ntake of Jeju ground water. These results suggest that consumption of Jeju ground water stimulated the antioxidant defense system in the livers of ob/ob mice via induction of Nrf2.

• Polymer(Korea)
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• v.35 no.6
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• pp.586-592
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• 2011

In this study, we synthesized vinylbenzyl chloride-co-styrene-co hydroxyethyl acrylate (VBC-co-St-co-HEA) copolymer that can be applied to redox the flow battery process. The anion exchange membrane was prepared by the amination and crosslinking of VBC-co-St-co-HEA copolymer. The chemical structure and thermal properties of VBC-co-St-co-HEA copolymer and aminated VBC-co-St-co-HEA(AVSH) membrane were characterized by FTIR, $^1H$ NMR, TGA, and GPC analysis. The membrane properties such as ion exchange capacity(IEC), electrical resistance, ion conductivity and efficiency of all-vanadium redox flow battery were measured. The IEC value, electrical resistance, and ion conductivity were 1.17 meq/g, $1.9{\Omega}{\cdot}cm^2$, 0.009 S/cm, respectively. The charge-discharge efficiency, voltage efficiency and energy efficiency from all-vanadium redox flow battery test were 99.5, 72.6 and 72.1%, respectively.

• Journal of the Korean Electrochemical Society
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• v.19 no.1
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• pp.21-27
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• 2016

Vanadium redox flow batteries (VRFBs) using the electrolytes containing various vanadium ions in sulfuric acid as supporting solution are one of the energy storage devices in alternatively charging and discharging operation modes. The positive electrolyte contains $V^{5+}/V^{4+}$ and the negative electrolyte $V^{2+}/V^{3+}$ depending on the operation mode. To prevent the mixing of two solutions, proton exchange membranes are mainly used in VRFBs. Nafion 117 could be the most promising candidate due to the strong oxidative property of $V^{5+}$ ion, but causes high crossover of electroactive species to result in a decrease in coulombic efficiency. In this study, the composite membranes using Nafion ionomer and porous polyethylene substrate were prepared to keep good chemical stability and to decrease the cost of membranes, and were compared to the properties and performance of the commercially available electrolyte membrane, Nafion 117. As a result, the water uptake and ionic conductivity of the composite membranes increased as the thickness of the composite membranes increased, but those of Nafion 117 slightly decreased. The permeability of vanadium ions for the composite membranes significantly decreased compared to that for Nafion 117. In a single cell test for the composite membranes, the voltage efficiency decreased and the coulombic efficiency increased, finally resulting in the similar energy efficiency. In conclusion, the less cost of the composite membranes by decreasing 6.4 wt.% of the amount of perfluorinated sulfonic acid polymer due to the introduction of porous substrate and lower vanadium ion permeability to decrease self-discharge were achieved than Nafion 117.

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.22-26
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• 1992

The solution structures of the vanadium(V) complexes of iminodiacetate analogues, such as iminodiacetate (IDA), methyliminodiacetate (MeIDA), ethyliminodiacetate (EtIDA), benzyliminodiacetate (BzIDA), pyridine-2,6-dicarboxylate (DPA), and 2-hydroxyethyliminodiacetate (HEIDA), have been studied by $^{13}C-$ and $^{51}V$-NMR spectroscopy. Assuming that the complexes have a $cis-VO_2$ core, IDA, MeIDA, EtIDA, and BzIDA act as facial tridentate ligands to form octahedral complexes, whereas DPA coordinates to $VO_2^+$ as a meridional tridentate. And one water molecule fulfills the remaining site to satisfy the coordination number of six. But HEIDA coordinates to $VO_2^+$ through one IDA moiety and one hydroxyl group, acting as a tetradenate.

• Polymer(Korea)
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• v.35 no.6
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• pp.593-598
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• 2011

The IPA-co-HDO-co-(TPA/MA) copolymers for all-vanadium redox flow battery were synthesized by melt condensation polymerization using isophthalic acid(IPA), 1,6-hexandiol (HDO), terephthalic acid(TPA) and maleic anhydride(MA). The amination of chloromethylated IPA-co- HDO-co-(TPA/MA)(CIHTM) copolymer was carried out using trimethylamine, and the anion exchange membrane was also prepared by UV crosslinking reaction. The structure and thermal stability of IHTM copolymers were confirmed by FTIR, $^1H$ NMR, and TGA analysis. The anion membrane properties such as water uptake, ion exchange capacity, electric resistance and electrical conductivity, were measured by gravimetry, titration and LCR meter. The efficiency of the all-vanadium redox flow battery was analyzed. The ion exchange capacity, electric resistance and electrical conductivity were 1.10 meq/g, $1.98{\Omega}{\cdot}cm^2$, and 0.009 S/cm, respectively. The efficiency of charge-discharge, voltage, and energy for the allvanadium redox flow battery were 96.5, 74.6, 70.0%, respectively.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.73-82
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• 2012

The main and side reactions of the three selective catalytic reduction (SCR) reactions with ammonia over a vanadium-based catalyst have been investigated using synthetic gas mixtures in the temperature range of $170{\sim}590^{\circ}C$. The three SCR reactions are standard SCR with pure NO, fast SCR with an equimolar mixture of NO and $NO_2$, and $NO_2$ SCR with pure $NO_2$. Vanadium based catalyst has no significant activity in NO oxidation to $NO_2$, while it has high activity for $NO_2$ decomposition at high temperatures. The selective catalytic oxidation of ammonia and the formation of nitrous oxide compete with the SCR reactions at the high temperatures. Water strongly inhibits the selective catalytic oxidation of ammonia and the formation of nitrous oxide, thus increasing the selectivity of the SCR reactions. However, the presence of water inhibits the SCR activity, most pronounced at low temperatures. In this study, the experimental results are analyzed by means of a dynamic one-dimensional isothermal heterogeneous plug-flow reactor (PFR) model according to the Eley-Rideal mechanism.

• Resources Recycling
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• v.26 no.4
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• pp.42-49
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• 2017

As a fundamental study for the separation of vanadium and tungsten from the leaching solution obtained from the soda roasting and water leaching process of spent SCR (Selective Catalytic Reduction) catalyst was carried out. The precipitation behaviors of vanadium and tungsten using the artificial solution (V: $1g{\cdot}L^{-1}$, W: $10g{\cdot}L^{-1}$) was investigated depending on temperature, NaOH concentration and the amount of $CaCl_2$ (aq.) added. V (aq.) was selectively precipitated at lower temperature than 293 K while tungsten also was precipitated at higher temperature. Precipitation rate of V and W was decreased by the increasing concentration of NaOH. On the other hand, excess Ca addition induced the increase of precipitation rate for V and W due to the formation of $Ca(OH)_2$ following the pH decline. The response surface methodology was employed to optimize the selective precipitation. Vanadium of 99.5% and tungsten of 0.0% was precipitated at $0.5mol{\cdot}L^{-1}$ of aqueous NaOH and 1 equivalent ratio of $CaCl_2$ at 293 K.

• Nutrition Research and Practice
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• v.8 no.2
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• pp.165-171
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• 2014

BACKGROUND: Groundwater is believed to possess many beneficial effects due to its natural source of various minerals. In this study, we examined the effects of natural Jeju groundwater S1 (Samdasoo$^{TM}$), S2 and S3 pumped up from different locations of Jeju Island, Korea, along with local tap water, on body weight gain, serum lipids and lipoproteins, and liver histopathology in high-fat diet-induced hyperlipidemic rats. MATERIALS/METHODS: Rats were randomly and equally divided into 6 groups. Different water samples were supplied to the hyperlipidemic rats as their daily drinking water and the widely-used anti-hyperlipidemic drug simvastatin was used as a positive control. Body weight, serum lipids and lipoproteins were measured weekly. Liver weight, liver index and liver histopathology were examined after the execution of the rats. RESULTS: After drinking Jeju groundwaters for two months, S2 but not S3 significantly reduced weight growth and serum triglycerides levels and increased high density lipoprotein-C (HDL-C) without affecting total cholesterol or LDL-C. S1 and particularly S2 significantly reduced the severity of liver hypertrophy and steatosis. All Groundwaters had much higher contents of vanadium (S3>S2>S1>>tap water) whereas S1 and S2 but not S3 markedly blocked autoxidation of ferrous ions. CONCLUSION: Jeju Groundwater S1 and particularly S2 exhibit protective effects against hyperlipidemia and fatty liver and hypothesize that the beneficial effect of Jeju Groundwaters may be contributed from blockade of autoxidation of ferrous ions rather than their high contents of vanadium.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.369-374
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• 2006

A solid-state reaction of $V_2O_5$ with AlMCM-48 followed by calcination generated very weak paramagnetic $VO^{2+}$ species in the mesoporous material. Dehydration and subsequent reduction with CO result in the formation of vanadyl $VO^{2+}$ species that can be characterized by EPR. The chemical environment of vanadium centers in $VO^{2+}-AlMCM-48$ was investigated by XRD, EDX, DR-UV-Vis, EPR,$^{29}Si$ and $^{27}Al$ and $^{51}V$ NMR. Vanadium species in MCM-48 are existed as pseudotetrahedral $VO^{2+}$ state when they were dehydrated or reduced with CO. The coordination of water on vanadyl ions transformed their structure to distorted octahedral.

• Resources Recycling
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• v.4 no.3
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• pp.32-39
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• 1995

Thc purpose of this study is to develop the efficient process for recovering vanadium and nickel from the incineralionash of the oil fly ash. In this paper, the physical and chemical properties of the incineration ash was examined, and theleaching characteristics of the incineration ash were investigated by water leaching and sulEuric acid leaching tcsls. The incinerationash of oil fly ash was mainly consisted of oxldes such as V,09, V,O,, NaVO,, Ni,(VO,)Z, Fe,O,, CaSO,, SiO,.Thc waler leaching showed low extraction of metallic components, while the sulfunc acid lcaching with high temperahlreand pressure increased the extraction of vanadium and nickcl considerably. For instance, the exlraction rates of the metalllccomponents on the sulfuric acid leaching were 99% for V and 45% for Ni at 90$^{\circ}$C with pH 0.5 H,SO,, and were86% for V and 75% far Ni at ZOO"C(64 psi) with pH 1.0 H-SO,. with pH 1.0 H-SO,.